validation/aggregating/*/*.sql: removed type-specific prefix from the view name, which is now part of the validation schema

inputs/import.stats.xls: updated import times

inputs/import.stats.xls: updated import times

schemas/vegbien.sql: analytical_stem.datasource: removed fkey to source.shortname because this prevents individually-reloaded datasources from being published

schemas/vegbien.sql: publish(), rm(): documented runtime (1 min)

schemas/vegbien.sql: added datasource_unpublish()

lib/sql_io.py: automatic handling of input/output column type mismatches: also do this for identifying columns, which first cause an error in a join in sql.distinct_table() rather than in the main insert (and thus were not handled by the existing error handling). previously, the user would have had to manually cast the input column in postprocess.sql. this involves getting handle_MissingCastException() to update join_cols as well as mapping.

lib/sql.py: distinct_table(): don't cache the table creation, because this prevents different distinct_tables from being created for the same input table

lib/sql.py: create_table(), copy_table_struct(): support custom query options, such as cacheable

lib/sql_io.py: put_table(): main loop MissingCastException handler: factored out into nested function so that it can also be used elsewhere